Help, please!!! What is the approximate perimeter of the square?

The lengths of nails produced in a factory are normally distributed with a mean of 4.91 centimeters and a standard deviation of 0.05 centimeters. find the two lengths that separate the top 4% and the bottom 4%. these lengths could serve as limits used to identify which nails should be rejected. round your answer to the nearest hundredth, if necessary.

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)

What is the number 321,000,000 in scientific notation? also what is the number? ?